Suspension setting theory and rollcenter revision technology which were the top secret when developing Tsukuba time attack specification "MOONFACE S15 SILVIA" are applied to the street tune. The rollcenter which is upset because of the vehicle height down is set up at the best position by the extended ball joint of suspension lower arm. After the long term repeated tests, we succeeded in reducing the rolling at cornering. No troubles about setting, and outstanding cornering speed, tire smoke as a proof of super traction are experienced. It draws out the potential at the stage of open races where drivers compete for the speed, or extreme drift battles. It is combined with various suspention parts and draws out the relish of sports running.